This invention relates to a vehicle control system of the kind having an open centre valve which controls operation of the first servo device, a closed centre valve which is fed from an accumulator and controls operation of a second servo device, the accumulator and open centre valve being fed from pump means which may be mechanically or electrically driven. Such a system is likely to be incorporated in a vehicle with the first servo device providing power assistance to a steering gear so that when a steering manoeuvre is not being effected the first valve is in its open centre condition and hydraulic fluid flows unrestrictedly by way of that valve in known manner. The second servo device may provide power assistance to operation of a brake or clutch which, when inoperative, locates the valve in its neutral or closed centre condition to prevent the flow of hydraulic fluid therethrough from the accumulator--again in known manner. With known power systems of this kind the output from the motor driven pump is supplied by way of a distributor to a system part which includes the first servo device and a second system part which includes the second servo device with the consequence that, whenever the accumulator requires charging, the whole of the pump output is raised to the accumulator pressure--Accordingly there may be a considerable wastage of energy in driving the pump motor (this is particularly so for an electrically driven pump where the electrical power drain can be excessive.) There is therefore a requirement for a control system of the kind discussed above which permits efficient utilisation of the energy which is available to supply hydraulic fluid under pressure to the servo devices and it is an object of the present invention to satisfy this requirement.